MHZS cd33 CD player, anyone tried one?

[PinkFloyd]

leo said:

Trying to find some more info on the dac used in the CD33 I stumbled across a thread where somebody decided to take the cover off the chip inside the more expensive CD66.
See the picture in the link below, oh look!!! it appears to be nothing more than a Burr Brown PCM1742 now can somebody please explain why these cdp's are advertised as using SUPER 24 BIT 192 KHZ DAC BY MHZS "WHICH BETTER THAN CS OR BB DAC" ;D
www.hififever.com/forum/download.php?id=7344

I knew I smelt a rat the first day I set eyes on it what with its fake "high end" caps, fake looking OPA2604, spurious "SONY" laser so this comes as no real surprise Leo

Thing is, it's not a bad sounding machine by any stretch of the imagination and is solid as a rock.... it's certainly worth the asking price but all that glitters in it is certainly not gold.

It's concerning to think that quite a lot of gear coming out of China may also be packed full of fake components and bullshit lies such as "MHZS" Dacs.......

If you have a read on Hi-Fi fever you'll see that MHZS is one of China's most respected and long time established audio firms....... jesus christ, if that's indicative of how a well respected company produce equipment then I will do my best to source homegrown gear every time

[leo]

Certainly agree with you Mike, its a nice piece of kit and I'm actually having some fun with it, amazing what difference this clock has made!
I'm actually pleased to find out it is a dac I know quite well so will make further modding easier lots more to try in it yet.

Still the build quality of it embarrasses a lot of units out there costing three times as much!

I just thought it was a little cheeky of them to post the dac is their own design and is better than Burr Brown

[PinkFloyd]

You may want to post on Hi-Fi Fever leo, they're a nice bunch over there Remember the two 2u2 (blue) polyprops are not stock, 220nF resides there so you may want to see what you think sounds best in this position. I have the original 220nF "musicaps" here if you want to try them though I doubt they are the genuine thing.

You're right, it is a nice piece of kit and could be a much nicer piece of kit without all the cloak and dagger components and strange (in places) layout.

Glad you are enjoying it man and the main reason I passed the baton over to you..... I just don't have the time to fck about with it what with a new GF on the scene (I'll be thinking differently in a couple of weeks once she goes all "committment" on me but at the moment I'm happy riding the groove) you enjoy it man and get your arse over to Hi-Fi Fever and put them straight on why the OPA 627 is running "hot"

Not my choice of chip in this app and, as you have discovered, no need for a chip at all

[leo]

I was going to email Pacific valve and ask them why its advertised as MHZS proprietary 24 bit DAC chip when it was designed by Burr Brown ;D

Regarding those Blue 2.2uf caps, these are very nice caps Mike! unless you'd like them back I'd be happy to stick with them tbh it should sound even better once the op-amp is bypassed and having those on the dacs output before the valves

I forgot about the GF, anyway sounds like your happy so thats great! my missus does not mind me fiddling about with this stuff, it keeps me out of trouble

[PinkFloyd]

leo said:

Regarding those Blue 2.2uf caps, these are very nice caps Mike! unless you'd like them back I'd be happy to stick with them tbh

My cap of choice in the X-10D..... EPCOS polyprops, lovely caps..... (lovely in that they don't add a "hello I'm a cap" signature..... very low insertion loss sonically IMO) for the money they are hard to beat.

The guys at Hi Fi Fever will be interested in your findings, I hope this finds it's way over there. OPA627 is a bad move IMO, no opamp is better but if the MHZS punter is not as bold / competent as you then what opamp would you recommend? I found the 2107 behaved a lot better than the 627 on Bdog (627 oscillated like mad) maybe best to stick to easy to work with chips like the 2132P / 2134pa?

I am so happy you're getting some hands on with this unit Leo, I kept homing in on the laser assembly and thinking "not worth the effort" have you any plans on swapping that out for something more robust? That will be the premature failure point IMO, if you could incorporate something beefy there you're laughing A potential powerhouse for very little outlay

Keep the pictures coming.

[leo]

Ok, update.
I've replaced the heater supply diodes to 1N5820 and the 4700uf 16v smoothing cap before the regulator to a Panasonic FA.

I have just bypassed the op-amp, I didn't have the exact value resistors so had to use what I had, a couple of 5k1 Holco's , 47k in series with 2k7 normal metal films for the 50k.
caps are 380pf polystyrene instead of 390pf and 47pf Mica instead of 39pf.
Well chaps I can fully recommend this mod to those who have one of these cdp's, it sounds rather nice
I know not everybody likes valves but somebody wanting a cdp with a valve output stage does not want to be hearing those op-amps so my advice is whip em out

[leo]

Oh and BTW those Epcos are really sounding damn fine now I've tried a few others here and must admit those Epcos are the best, good choice there mr Pink!

[PinkFloyd]

leo said:

Regarding those Blue 2.2uf caps, these are very nice caps Mike! unless you'd like them back I'd be happy to stick with them tbh

My cap of choice in the X-10D..... EPCOS polyprops, lovely caps..... (lovely in that they don't add a "hello I'm a cap" signature..... very low insertion loss sonically IMO) for the money they are hard to beat.

The guys at Hi Fi Fever will be interested in your findings, I hope this finds it's way over there. OPA627 is a bad move IMO, no opamp is better but if the MHZS punter is not as bold / competent as you then what opamp would you recommend? I found the 2107 behaved a lot better than the 627 on Bdog (627 oscillated like mad) maybe best to stick to easy to work with chips like the 2132P / 2134pa?

I am so happy you're getting some hands on with this unit Leo, I kept homing in on the laser assembly and thinking "not worth the effort" have you any plans on swapping that out for something more robust? That will be the premature failure point IMO, if you could incorporate something beefy there you're laughing A potential powerhouse for very little outlay

Keep the pictures coming.

[leo]

Totally agree and I must admit this is the first time I've heard these caps as a DC coupler, they beat the pants off a pair of Auricaps and Rel-caps (to my ears)

I actually have a spare Sony KSS-213C laser spare so will try it out and see if its a direct replacement for this copy
It would be interesting to see what other transports could be bodged in there

The main problem with this CDP is layout, theres long tracks from those whopping great 2200uf decoupling caps after the regs, I think the added extra of the browndog adapters is enough to make it go unstable, you could see it ringing on the scope.
I was going to add a pair of 47/100uf local decoupling caps fitted onto the pins to nearest ground like I did in the Chiarra if in the small off chance I didn't like it with the op-amps bypassed.

Once I have removed the op-amps supply and parts of the circuitry no longer needed I'll post another picture and keep posting more after other tweaks have been tried.


Oh BTW www.hififever.com/forum/viewtopic.php?t=952&postdays=0&postorder=asc&start=650&sid=32650f42609ebc05feab1c9f45acbfe0

[PinkFloyd]

hehe..... your cat would get on well with alfcat Leo

[leo]

Quick update.
Op-amp and op-amp regulation removed, standard onboard 5v regulation supplying dac bypassed and now run from a VBE modified ALW super reg.
Output coupling capacitors replaced to Arcotronic polypropylenes (all I had spare)

May try a CCS for the valves

[Deleted]

Leo
How many VA is the toroidal tranny ?
Alex

[leo]

Alex,
I've no idea theres no markings or anything printed on it, its nice to see that it does have multiple secondaries so each part of the unit has separate supplies.

I was actually getting some very good sound out of this unit last night, the 5v super reg has brought a worthwhile improvement

[Deleted]

It just seems awfully small in the photo. Perhaps in real life it is bigger ?

[leo]

The secondary wiring looks quite thick, its also quite a tall toroidal, even with the valves heater current the temp of the traffo is cold with no buzzing, theres 4700uf caps for the main smoothing for each supply, the traffo is quite quiet for a toroidal.
It could be upgraded but finding a suitable type with all the different secondaries of this one would prove to be hard and expensive, maybe if there was far less secondary outputs feeding more circuitry it would be different

[leo]

A few more mods

[matthewr]

Hi i am new here - due to owning one of these cd players.
Question 1 - are these really HDCD players? I see that they do not have the MHZS dacs, but are they still 24bit?

Is any one willing to do mods for other members?
thanks
Matthew T. Rondeau

[leo]

Hi Mathew,

The CD33 I have isn't HDCD but the newer SE version is it seems although I can't confirm how true that is because I've not seen the insides.
They already lied about the dac chip
The PCM1742 used in mine is classed as 24bit, I wouldn't really take much notice of the rated bits a chip has though

If I had the time I'd offer to mod it for you but at the moment, I'm struggling to get spare time to do my own stuff at the mo

[matthewr]

Hey again,
My unit does make a difference when you change the sampling frequency - at least I an thinking it did. can some one please explain what is going on with that - if it is trully not HD than will it really make a difference when you change the sampling frequency?
what would be the biggest bang for the buck for a mod?
Thanks
Im really not a tech, so - but i can solder when required. I love to improve things. Thanks every one.
Matt

[leo]

You should be able to hear a small difference regarding the sampling, its actually quite subtle in the CD33 but can be much more noticeable in some other units, all your doing is multiplying the sampling rate, its supposed to improve jitter/errors.
Upsampling can also add problems if not implemented properly, EVERY single unit I've heard so far using upsampling adds a signature making the music sound more alive,detailed etc, some may class it as euphonic.
It may sound better with some types of music better than others

Hard to say what the biggest bang for buck is regarding mods, problem is you start improving one part and it often shows up other flaws in the circuit especially in this unit.
Easiest to try first is better decoupling and coupling caps, fit a 8-pin socket to allow easy op-amp rolling, improve the diodes.

[dmonte]

hello

Don't mean to hijack, I have the 88 E top load version for about two months now and it's starting to show the "no disk" error when I'm trying to load CD after numerous attempts it will still play though, any suggestions of the cause? the seller will not even respond to e-mails

[mrarroyo]

Have you tried cleaning the lens and surrounding area? If not use compressed air and a soft long hair brush.

[dmonte]

yes thank you, that is what I've been doing to get it to work so far. Just now I tried again and it came up with the no disk message, after wiggling the puck a bit and trying a few times I got it to work again.

RichTonaudio on eBay that I purchased it from just got back to me recommending that I should take out the laser pickup and send it to them for replacement.

Wondering if I should do that or just asked them how much they can just send me an extra one considering the price of shipping the old one back. Are these pickups expensive?

[mrarroyo]

I would ask for them to send you the replacement and an pre-paid label to send the laser pickup.

Ideally they should send you a new unit w/ a pre-paid label so you can send back the mal-functioning unit.

[leo]

dmonte said:

hello

Don't mean to hijack, I have the 88 E top load version for about two months now and it's starting to show the "no disk" error when I'm trying to load CD after numerous attempts it will still play though, any suggestions of the cause? the seller will not even respond to e-mails

Could be a few things causing this, main one is the laser head unit is on the way out, these are actually copys of the Sony units so the quality is unknown, the good news is that the original Sony units are supposed to be a direct replacement and not too expensive but I can't confirm it as I've not tried it.
Its also possible the spindle puck that the disc sits on may have slightly dropped down, if these are not set to the right height then the laser struggles to read the TOC, they sometimes slightly drop down the spindle after some use

The ribbon cable from the mechanism would be worth checking, the one in this CD33 is a little temperamental mainly the sockets